Latch operated clutch



April 5, 1949.

` E. P. sPAlNE 2,466,500

LATCH OPERATED CLUTCH Filed vJuly 16, 1945 Sme/wm WAlt'new A m43Patented Apr. 5, 1949 UNITED STATES PATENT OFFICE LATCH OPERATED CLUTCHEdward P. Spaine, Bridgeport, Conn., assignor to The SingerManufacturing Company, Elizabeth, N. J., a corporation of New JerseyApplication July 16, 1945, Serial No. 605,245

7 Claims.

This invention relates to clutches and particularly to that type ofclutch used extensively in buttonhole sewing machines which are designedto make a predetermined number of revolutions and are then brought to adefinite stop position. A machine of the type in question is disclosedin the U. S. patent of E. B. Allen, No. 863,129, Aug. 13, 1907, in whichpatent is illustrated the speciic form of clutch upon which the presentinvention is an improvement.

In the prior construction, it was customary to employ only oneclutch-element to connect or disconnect the belt-driven driving pulleyand the main-shaft of the machine. When using only one clutch-element,the driving pulley is clutched to the main-shaft by a separating actionof the clutch components, which separating action resuits in the forcingof the hub-bore of the driving pulley into frictional engagement withthe periphery of the main-shaft. As a result of the diierence in thedistances from the center of the main-shaft to the periphery of themain-shaft and to the clutch-face on the driving pulley, slippagesometimes occurs between the main-shaft and the pulley-hub-bore engagingthe shaft. This slippage results in the generation of heat sufficient tocause the driving pulley to seize on the mainshaft and, Ifrequently,also to cause the mainshaft to run-up in its adjacent bearing.

It is therefore the primary object of the present invention to provide aclutch of the type in question designed to eliminate the slippagebetween the driving pulley and the main shaft when the clutch-elementsare in wedging relation.

Another object of the invention is the provision of a clutch whichremains in declutched condition during any slight rebound of themechanism resulting from the sudden stopping thereof.

Other objects of the invention and the features employed to accomplishsuch objects Will be apparent when the following description isconsidered in connection with the accompanying drawings.

In the drawings:

Fig. 1 is an end elevational view of the clutch in effective drivingposition, with the retainercollar broken away to expose certain of thedetails of the clutch. y

Fig. 2 represents a sectional view taken substantially along the line2-2, Fig. 1.

Fig. 3 represents a vertical sectional View taken substantially alongthe line 3 3, Fig. 2.

Fig. 4 is an end elevational view similar to Fig. 1, but with a portionof the stop-mechanism 2 of the sewing machine in position to effect adeclutching of the driving belt-pulley.

Fig. 5 is a perspective view of the driven element of the clutch.

Fig. 6 is a perspective view of the driving element of the clutch.

Referring to the drawings which illustrate a preferred embodiment of theinvention, the clutch assembly is shown as mounted on a sewing machinemain-shaft I 0. Freely journaled on the main-shaft I0 is a gear II ofwhich the extended hub-sleeve I2 has keyed thereon a belt-driven drivingpulley I3. Formed in a side face of the pulley I3 is an annular recessI4 providing an internal concentric cylindrical clutch-face I5. Disposedwithin the recess I4 is a driven clutchmember I 6 having a hub I'Isecured on the mainshaft I0, preferably by means of a taper-pin I8 and aset-screw I9. As shown in Fig. 5, the driven clutch-member IB is formedwith a segmental slot 20 and a clearance cut-out 2|. Disposed inface-to-face relation with the driven clutch-member I6 is aclutch-element-carrying member or clutch-ring 22 having a centrallylocated clearance-hole 23 through which projects the hub Il of thedriven clutch-member I6. Projecting from the inner face of theclutch-ring 22 is a fulcrumlug 24 and an abutment-lug 25. The fulcrumlug24 extends into, and is embraced by the sides of, the segmental slot 20in the driven clutchmember I6, while the abutment-lug 25 extends intothe clearance cut-out 2|. When the driven clutch-member I6 and theclutch-ring 22 are thus assembled, the clutch-ring is adapted to pivotslightly about the fulcrum-lug 213 relative to the driven clutch-memberI6; the extent of relative movement being determined by the differencein sizes of the clearance-hole 23 and the hub II. To prevent excessivepivotal bodily movement of the clutch-ring 22, the driven clutch-memberhub II is formed with a stop-abutment 26, clearly shown in Fig. 5.

To provide for connecting the driven clutchmember I6 to the drivingclutch-member or pulley I3, I have employed two clutch-elements orcylinders 2l and 28 which are positioned opposite each othersubstantially diametrically of the clutch-ring 22. The clutch-cylinder2l is located in a half-round cavity 29 extending lengthwise of, andopening into, the periphery of the fulcrumlug 24, whereby theclutch-cylinder, when located in said cavity, can engage the internalcylindrical clutch-face I5 of the driving clutch-pulley I 3. The otherclutch-cylinder 28 is disposed in a second cavity 30, the bottom ofwhich is dened by the inclined outer end-surface 3 I of the abutmentlug25 and the sides of which are dened by the extended inclined faces 32and 33 of two plates 34 and 35 secured, preferably by the screw 36, tothe opposite sides of the abutment-lug.

The two clutch-cylinders 21 and 28 are normally urged into :clutching orwedg-mgr relation between .theeclutch-ring22 andithe drivingclutchmember or pulley I3 by a relatively strong coilspring 31positioned in a curved spring-receiving chamber 38 formed in the drivenclutch-member I6. As clearly illustrated in Fig. V3, one end -o'f thecoil-spring 31 rests against the closed end-39 of its chamber 38 and theother Vend'bears against the abutment-lug 25 of the clutch-ring 22. Toprevent accidental displacement of that .end of the spring 31 contactingthe abutment-lug 2`5,`t`he'1a`st convolution of the spring is preferablysized to embrace a nut 40 threaded upon the screw 36. It will `beobvious from the drawings that the coil-spring acts ,between the .drivenclutch-member I6 and the :clutch-ring .2.2, and .that through thecoil-spring, these two components of .the clutch are urged apart about`the fulcrum-lug 2l.

As illustrated in Fig. 4, the clutch-cylinders 21, 28 are `disposed atsubstantially diametrically opposite sides -of the `pulley clutch-faceYAI .when said clutch-cylinders are in the clutch-release position inwhich they lare held by a .stop-motion plunger 4I ydisposed in astop-notch 42 provided i-n 'the periphery of the .clutch-ring 22. Uponwithdrawal of the .plunger 4I from `thestop-no'tch 42, :the lreleasedclutch-ring 22 is 4free to swing about the fulcrum-lug V2II, therebypositioning the clutch-cylinders 21 and 28 OIT-center or out ofdiametrical relation with .respect to the clutchface I5 `of the pulley,as illustrated in Fig.. "1 o'f the drawings. This `results in -wedgingthe clutch-cylinders 21, 2'8 against the pulley clutchface t5 and inthereby inducing rotation ci the clutch-member I6 with the pulley I3 .inthe "direction -of the arrow kshown in Fig. '1. VAs 'the driving actionof the pulley I3 is transmitted through the `clutch-cylinders 21 and `28-to Athe clutch-member I6 vat opposite sides of the pulley, binding ofthe pulley-hub-bore on the mainshaft is thereby eliminated.

When it is desired to interrupt the driving 'relationship between thebelt-pulley `I3 and 'the shaft I8, the automatically operatedspring-depressed stop-motion plunger, indicated generally as 4I in Fig.4, is adapted to enter the stop-notch 42 formed in the clutch-ring 22.When this occurs, the coil-spring 31 is compressed andthe clutch-ring 22pivots, in a clockwise direction (Fig. 4)-, about its fulcrum-lug 2lrelative to the driven clutch-member I6 and into a position determinedby the stop-abutment 26. With the parts in this position, theclutch-cylinders 21 and 28 have been shifted into a location in whichwedging action cannot occur. When the clutchcylinders 21 and 28 are innon-wedging position, as shown in Fig. 4, rotation of the declutchedpulley I3 causes the clutch-cylinders to rotate in their respectivecavities. clutch-cylinders is effective to change the wedging surface onthe cylinders, thus distributing 'the wear about the entire periphery ofthe cylinders.

As is fully explained in the above mentioned U. S. Patent No. 863,129,that portion of the periphery of the clutch-ring 22, in advance of thestop-notch, is formed with a cam-rise '43 which is. utilized to elevatethe stop-motion plunger `so that the same can drop into the stop-notch42 when the usual stop-motion lever is tripped to This rotation of thestop the machine. The action of the cam-rise 43, in elevating thestop-plunger 4I, elects a braking action on the machine, which resultsin easing the blow of the clutch-ring 22 against the stop-plunger 4I.The shock of suddenly stopping the machine is absorbed by thecoil-spring 31. To prevent -the accidental reclutching of the 'drivingpulley I3 with the main-shaft ID during any rebound which might occurfrom the sudden stopping of the machine, the outer end-surface `3I ofthe abutment-lug 25 is inclined. The inclination of this surface or seatprovides clear- .ancefor the -clutch-cylinder 28, see Fig. 4, whichV1clearanceissuiii'cient so that the clutch-elements 2'1 and 523 cannotenter into wedging relation between the cylindrical clutch-face I5 ofthe 4ldri-ving pulley 13 and the clutch-element-carrying member 22, inview of the small amount of relative shift between the driven member I6and the clutch-element-carrying member 22 resulting from the rebound.Moreover, the inclination of the jsea't 3I is effective to lessen thestarting load shock. Referring to Fig. 4, it will 'be `appreciated thatwhen the stopping mechanism is ''rst released, the clutch-ring 22, underthe inuence "of the coil-spring l31, swings about the fulcrum-'lug 24,`causing the clutch-'cylinder 28 to 'engage the cylindrical clutch-faceI5. The initial engagement of 'the clutch-cylinder 28 causesthefulcrum-lug r24 on the clutch-ring 22 to #shift outwardly in itssegmental slot 20, thus forcing the clutch-cylinder 21 into contactlwith 'the 'cylindrical :clutch-face I5. Following this, theclutch-cylinder 28 rolls down its inclined seat '3I into its finallocking or wedging position. During this sequence of actions, thestarting load is gradually absorbed sc that when final clutching takesplace, the parts are not subjected to a sudden heavy shock.

`To provide for maintaining the component parts 'of 'theyclutch-mechanism in face-to-face cooperative relationship, th'emain-shaft I0 has `secured thereon, by means of a set-screw 44 and the`taper-pin I8, a retainer-collar `45 having its inner face contactingthe outer face `of the clutch-ring 2`2 (Fig. 12).

From the above description taken in connection with the accompanyingdrawings, it will be appreciated that I have perfected .aclutchm'echanis'm "of the type in question in which the clutching of thedriving and driven members occurs at substantially diametricallyopposite points thereby eliminating the binding of the driving memberlon the shaft upon which it is journaled. In addition, I have eliminatedthe 4accidental reclutching of the driving and driven members, in theevent any slight rebound occurs as a result of the abrupt stopping ofthe operating machine parts. Also, I have perfected a clutch mechanismof the type in question which can be manufactured cheaply, primarily forthe reason that a lclose tolerance is not required on the various partsin order for the clutch to operate satisfactorily.

While I have shown the coil-spring 31 to be relatively strong, it is lsomade only because of the load it must'assume in suddenly stopping themachine. It will be appreciated that any weak spring having suicientstrength to shift the clutch-ring 22 relative 4to the clutch-member I6to bring the clutch-cylinder 28 into contact with the 'internalclutch-'face I5, would `successfully operate to effect a clutching ofthe driving pulley I3 to the main-shaft I0. The iinal wedging acnon ofthe clutch-eminem 21 and za 4is effected by the rotation of the drivingpulley i3 and not by the coil-spring 31.

Having thus set forth the nature of the invention, what I claim hereinis:

1. A clutch-mechanism comprising a driving member rotatable about anaxis, a driven meinber, a clutch-element-carrying member pivotallysupported on said driven member for movement about an axis spaced to oneside of the axis of rotation of said driving member, a clutch-elementsustained by said clutch-element carrying member at the other side ofthe aXis of rotation of said driving member, a spring acting betweensaid driven member and said clutch-elementcarrying member for causing arelative shift between said two last named members to eifect engagementof said clutch-element with said driving member, releasable meansopposing effective action of said spring, and means eiTective in theclutch-release position of the clutch-eleu ment-carrying member forpreventing reclutching of said clutch-element and said driving memberupon rebound reverse rotation of said driven member.

2. A clutch-mechanism comprising a shaft, a driving member journaled onsaid shaft and having a cylindrical clutch-face, a driven member fast onsaid shaft and formed with a segmental slot, a clutch-element-carryingmember provided with a fulcrum-lug and an abutment-lug, said fulcrum-lugbeing disposed in said segmental slot for cooperation therewith toprovide a pivotal connection between said driven member and saidclutch-element-carrying member, a plurality of clutch-elementsinterposed between the cylindrical clutch-face of said driving memberand said clutch-element-carrying member, and a spring acting betweensaid driven member and the abutment-lug on said clutch-element-carryingmember for inducing a relative pivotal shift between said two last namedmembers, thereby to urge said clutch-elements into engagement with saiddriving member.

3. A clutch-mechanism comprising a driving member having a cylindricalclutch-face, a driven member peripherally formed with a segmental slot,a clutch-element-carrying member provided with a fulcrum-lug and anabutmentlug formed with a cavity, said fulcrum-lug projecting into andcooperating with said segmental slot to provide a pivotal connectionbetween said driven member and said clutch-element-carrying member, aclutch-element disposed in said cavity and located to cooperate with thecylindrical clutch-face of said driving member, means acting betweensaid driven member and said abutment-lug for inducing a relative pivotalshift between said driven member and said clutch-element-carrying memberfor moving said clutchelement into clutching engagement with saiddriving member, declutching means for interrupting the clutchingengagement of said clutch-element, and means providing clearance forsaid clutch-element and eleotive to eliminate accidental reclutching ofthe driving and driven members during any slight rebound of the drivenmember resulting from the operation of the declutching means.

4. The stop-mechanism as set forth in claim 3, in which the meansoperative to eliminate accidental reclutching of the driving and drivenmembers during any slight rebound resulting from the operation of thedeclutching means, comprises having the bottom surface of theclutch-element cavity provided in said abutment-lug disposed to providean increasing clearance in the direction oi normal rotation of saiddriven member.

5. A clutch-mechanism comprising a driving member having a cylindricalclutch-face, a driven member formed with a segmental slot, aclntch-element-carrying member provided with a fulcrum-lug formed with acavity and an abutment-lug also formed with a cavity, said fulcrumlugprojecting into and cooperating with said segmental slot to provide apivotal connection between said driven member and saidclutch-element-carrying member, a clutch-element disposed in each ofsaid cavities formed in said clutch-element-carrying member and locatedto cooperate with the cylindrical clutch-face of said driving member,and a spring acting between said driven member and said abutment-lug forcausing a relative pivotal shift between said driven member and saidclutch-element-carrying member, thereby to urge said clutch-elementsinto engagement with said driving member.

6. A clutch-mechanism comprising coaXially disposed driving and drivenrotary clutch-members, one of said clutch-members having an annularrecess providing a cylindrical clutch face concentric therewith, acarrier-member pivotally mounted upon the other one of saidclutch-members for swinging movement about an axis parallel to thecommon axis of rotation of said clutchmembers, clutch-elements carriedby said carrier-member at opposite sides of the rotation aXis of saidcarrier-member and disposed for engagement with said cylindricalclutch-face, and spring means inducing swinging movement of saidcarrier-member in a direction for effecting clutching engagement of saidclutch-elements with said cylindrical clutch-face.

7. A clutch-mechanism comprising a rotary driving member having acylindrical clutch-face, a rotary driven member, a carrier memberpivotally mounted upon said driven member for swinging movement andhaving a plurality of clutch-element receiving cavities adjacent saidcylindrical clutch-face, one of said cavities having a face opposed toand inclined away from said clutch-face in the direction of rotation ofsaid driving and driven members, clutch-elements disposed in saidcavities, and spring means inducing swinging movement of saidcarrier-member in a direction for effecting clutching engagement of saidclutch-elements with said cylindrical clutchface.

EDWARD P. SPAINE.

REFERENCES CITED The following references are of record in the ile ci tpatent:

UNITED STATES PATENTS Number Name Date 503,311 Dahl Aug. 15, 1893658,520 Abel Sept. 25, 1900 1,968,771 Jex July 31, 1934 2,072,852 Battenet al. Mar. 9, 1937

